21/32,1,25/24,17/18,43/54,

21/32=7/(32/3)=7/(2的5次方*3的-1次方）1=16/16=16/(2^4*3^0)25/24=25/(2^3*3^1)17/18=34/36=34/(2^2*3^2)43/54=43/(2*3^3)分母为公差9的等差数列,分母3/2的等比数列所以（）=（43+9）/(2^0*3^4)=52/81...